docs: def get_report(self):
          """
          Return a string containing a report of the result.
          This can used to print or save to a text file.
  
          Returns:
              str: String containing infos about the result
          """
  
          lines = [super(InvalidUtterancesResult, self).get_report()]
  
          if len(self.invalid_utterances) > 0:
              lines.append('\nInvalid utterances:')
  
              sorted_items = sorted(self.invalid_utterances.items(), key=lambda x: x[0])
              lines.extend(['    * {} ({})'.format(x, y) for x, y in sorted_items])
  
          return '\n'.join(lines)